The clinical characteristics of patients with intumescent cataracts include complete lens opacity and lack of red reflex, making it difficult to visualize the capsule edge during capsulorrhexis, which becomes one of the challenges in the surgical procedure. To address this issue, scholars both domestically and abroad have attempted methods such as staining the lens capsule with indocyanine green or trypan blue, which have been shown to improve the success rate of capsulorrhexis in these patients to some extent[1]. However, for patients with cortically liquefied intumescent cataracts, simple staining only enhances visibility. During capsulorrhexis, the instantaneous opening of the capsule under pressure gradients within the capsule can lead to complications such as the Argentinian flag sign[5] (Fig. 1). Therefore, achieving continuous curvilinear capsulorhexis in this type of cataract remains a clinical challenge.
To address this issue, scholars have focused on two main aspects: how to appropriately increase anterior chamber pressure to counteract anterior capsule tension, and how to open the anterior capsule to release pressure within the capsule and avoid linear capsule tears. Bhattacharjee et al. reported the use of viscoelastic agents to fill the anterior chamber, thereby increasing anterior chamber pressure[6]. Some researchers have also used two different types of viscoelastic agents (dispersive and cohesive) injected into the anterior chamber to reduce the risk of anterior capsule rupture [3]. F Ucar used continuous fluid pressure and anterior chamber maintainers to increase anterior chamber pressure[7]. However, excessive use of viscoelastic agents or anterior chamber irrigation can lead to increased overall anterior chamber pressure, damage to zonules, compression of the posterior segment, or even the occurrence of reverse Argentinian flag sign[8]. Another aspect is the use of different techniques to open the anterior capsule and release pressure within the capsule to avoid excessive tension on the capsule, leading to linear capsule tears. Porwal et al. performed Nd:YAG laser anterior capsulotomy before cataract surgery to relieve pressure within the capsule[9]. In recent years, with the development of femtosecond laser-assisted cataract surgery (FLACS), many ophthalmologists have begun using femtosecond laser instead of manual capsulorrhexis[10]. However, even with the latest FLACS technology, consistent capsulorrhexis cannot be guaranteed in the treatment of intumescent cataracts, and there have been several reports of Argentinian flag sign complications related to FLACS in intumescent cataracts[11]. Some scholars have reported the use of nanosecond pulse technology, nitinol rings, and other techniques for anterior capsulotomy, but these techniques require new equipment, increasing financial burden on patients, and their safety has not been clinically confirmed[12]. Other methods include the use of vitreous cutter needles, superotemporal incisions, stab knives, 25–27 gauge needles, and extremely fine 30G insulin syringe needles for anterior capsulotomy[13, 14, 15]. Numerous newly reported techniques such as vacuum capsulorrhexis, modified two-step methods, and suture needle microcapsulotomy have also been attempted [16, 17, 18, 19]. Although these methods have shown some effectiveness, they still cannot completely eliminate the risk of anterior capsule tears and varying degrees of Argentinian flag sign occurrence[10]. Therefore, to achieve successful continuous curvilinear capsulorhexis, it is necessary not only to reduce surface capsule tension and avoid triggering the Argentinian flag sign at the moment of initial capsular rupture but also to release pressure in the posterior chamber simultaneously with the formation of the capsulorrhexis to prevent extension of the tear. However, most existing studies have only proposed solutions for one of these risk factors, indicating that exploring new treatment methods still holds significant clinical importance.
Based on the biomechanical research of the lens capsule, in order to effectively prevent the occurrence of the Argentinian flag sign, we adopted a combined approach of anterior chamber bubble technique and cortical fluid release technique to balance the pressure between the anterior and posterior chambers. Firstly, we utilized the anterior chamber bubble technique to reduce surface capsule tension, avoiding the immediate triggering of the Argentinian flag sign at the moment of initial capsular rupture. Subsequently, the cortical fluid release technique was employed to release the pressure in the posterior chamber simultaneously with the formation of the capsulorrhexis, preventing extension of the tear and facilitating smooth curvilinear capsulorhexis.
Specifically, a small amount of viscoelastic agent was injected into the anterior chamber to maintain the anterior chamber, exerting pressure on the anterior capsule. Then, a sterile air bubble (diameter 5mm) was injected into the anterior chamber to increase pressure on the central capsule, i.e., the pressure of the viscoelastic agent (blue arrow) combined with the tension of the air bubble (green arrow), counteracting the outward pressure from within the lens (red arrow), thereby flattening and relaxing the anterior capsule in the central area, reducing tension. When the pressure exerted on the central capsule area by the bubble exceeded that on the surrounding capsule, this area of the anterior capsule became flat and relaxed, resulting in reduced tension. This approach prevents the occurrence of the Argentinian flag sign due to excessive capsule tension at the initial capsular rupture. It is important to note that after opening the capsule, to prevent upward movement of the nucleus leading to capsule rupture, we utilized the puncture needle described earlier in the flat and relaxed central anterior capsule. Specifically, a No. 5 head scalp needle with a bent angle of approximately 135° was connected to a syringe after bending, and was used to puncture the anterior membrane in the central area. This allowed for aspiration of the liquefied cortex while simultaneously pushing the nucleus backward with the needle, breaking the equatorial barrier. This facilitated fluid flow from behind the nucleus into the anterior chamber, thereby controlling the pressure in the posterior chamber of the lens, which is also a critical aspect of this method. By employing this approach, we eliminated the expansive state of the lens, successfully completing curvilinear capsulorhexis in every case, and avoiding the occurrence of the Argentinian flag sign. The advantage of our approach lies in proposing avoidance methods for potential risks at each step of the procedure, ensuring the smooth completion of capsulorrhexis and subsequent operations.
In this study, we innovatively proposed the combined approach of anterior chamber bubble technique and cortical fluid release technique, which was clinically proven to effectively prevent the occurrence of the Argentinian flag sign in patients with cortically liquefied intumescent cataracts. Furthermore, this method does not require additional instruments, reducing the risk of surgical infection, does not increase patient surgical costs, is simple and convenient to operate, and is easy to learn and promote. In the future, we will continue to refine the classification of intumescent cataracts and propose more targeted and effective treatment methods for patients with cortically liquefied intumescent cataracts, enabling more precise selection of surgical approaches and improving surgical success rates.
In this study, none of the 50 eyes included experienced the Argentinian flag sign during surgery, and all patients achieved ideal vision at the end of follow-up without postoperative complications. However, the sample size in this study was small, and the follow-up time was short. In the future, we will continue to increase the clinical sample size, extend the follow-up time, and further investigate the differences in intraoperative and postoperative efficacy between this method and other methods in patients with cortically liquefied intumescent cataracts.